Synchronous electric clock motor



Jan. 5, 1954 F. J. LANDGRAF ET AL ,389 SYNCHRONOUS ELECTRIC CLOCK MOTOR Filed Jan. 16, 1952 2 Sheets-Sheet 2 INVENTORS FRANCIS J. LANDGRAF 8. RICHARD P. LANDGRAF AGENT Patented Jan. 5, 1954 2,665,389 sY enaoNoUs ELECTRIC croc oron- F c s La dert an ha d Lanslz e r Chicago, Ill.

Application January 16, 1952; Serial No 266 726 1 Claim, (01- 3.971541 The present invention relates generally,v to.

It is a primary object of the invention to pro-. vide a novel motor of the classindicated which is capable of particularly economical production, is rugged and compact, and possesses good operating characteristics.-

It is a more particular object of the invention to provide a novel motor ofthe class indicated which is fabricated of. a minimum numberv of simpleparts.

It is a iurtherobject of theinvention to provide-a motor of the class indicatedhaving concentrated field flux for the number of ampere turns of field winding employed, by virtue of employment of a field winding coaxial with the rotor, and having a tapering cross section.

It is another object of the invention toprovide a novel motor of the class indicated in which the parts of the motor involve no metal drawing operations, but may be stamped or die pressed.

Still a further, objector thelinvention resides in the provision of a motor of the class indicated in which oneof the-poleaplates is provided with bearings for gear shafts of an electric clock or the like, thereby reducing the overall expense of including the motor in an electric clock;

Still'another object of the invention resides in the provision'of an electric motor of the type in: dicated in which pole pieces are formed integrally with the pole plates, and in which shading ringsare pressed over the pole plates, the ring pole pieces inwardly of the field winding being tapered to have a width such that its outmost width forms a spacer for the pole plates, while its inner width clears the shading rings.

Still further objects, features, and advantages of the invention will become apparent upon consideration of the following detailed description of one specific embodiment of a motor constructed in accordance with the invention, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is an explosion of a motor constructed and arranged in accordance with the present invention;

Figure 2 is a traverse section of a motor of Figure 1 assembled; and

Figure 3 is a view in elevation of some of the elements of the motor of Figure 1 in assembled relation.

Referring now more particularly to the drawings the reference numeral l indicates generally a motor, of the self-starting shaded pole synhighly 2. chronous type,- employing a hysteresisetype. rotor;-v 2; consisting of'a disc 3 .of aluminumor'othec light non-magnetic material, the latter beingprovided with a thin rim fabricated of steel -hav-. ing high remanence. The rim 4 maybe of slightly greater. width than the disc 3,. and the-latter may be provided with a plurality of symmetrically distributed apertures 5. The disc 3 is force. fittedto acentral motor shaft or arbor 6, which is, in the assembled motor, journaled in bearings 7. The bearings"! are forcefittedinto disc-likepoleplates 9,. I 0, dieformed-of steel. The pole plate his provided with bearing apertures, as] I, to receive the endsofshaftsorarbors, as. I2, which support the gears and pinionsof a clock (not shown), thereby reducing the total number-oi parts required in a clock assembly.

Poleifingers 3 are die formed integrally/with the pole plates, in adjacent pairs, there being-inall ten pairs ofpole fingers formediromeachplate, and each pair providing one field: pole electrically- The spacing of the pole finger-pairs is so arranged thatthepole finger-pairs deriv ingfromthe separate pole plates intermesh',-; andthepair of poleplates to be. assembled into a -.single motor may be identical generally, except forthe presence of the bearing apertures it in one pole plate, which-are not required in the other.

A separate pair of shading-rings -I E-isprovided, apertured for force fitting over the pole fingers; iii of each pole plate and lyingfiush against-thepole-plate.-- A radial slit -l6-is provided in--the shading rings for one of each pair of pole fingers, the slits being equally spaced about the shading rings I 5. The latter may be die formed from sheet copper or other non-magnetic material having the requisite electrical conductivity. Accordingly, the pole fingers i3 afford reinforcement for the shading rings l5, and the rings l5, being rigid, support and retain the spacing of the pole fingers, forming a rigid, yet easily assembled whole. By reason of the slits IS an electrical circuit is established through the rings about alternate ones only of the pole fingers, and in consequence half the effective area of each pole, comprised of a pair of adjacent pole fingers, is shaded and half unshaded.

A similar shading ring arrangement is provided for each of the pole plates, with the diiference that locations of the slits l6 are such that if the counterclockwise fingers of each pair are shaded on one pole face, the clockwise fingers are shaded on the other, when similarly viewed. In consequence when the pole faces are assembled,

the sense of shading is identical for both, and effectively 20 similar shaded poles are provided, the pole fingers of which are all equally spaced circumferentially.

A field winding i8 is wound in a tapered plastic shell I9, wider at greater radius. The maximum width of the shell 19 is such that the shell forms a spacer for the pole plates I3, or is clamped therebetween, retaining the ends of the pole fingers just out of contact with the shading rings.

A further spacing member is provided by the outer steel closure ring 20, which has the same Width as the maximum width of the shell 19.

The closure ring 20 is split along its width, and provided with an aperture 2!, straddling the split, to enable emergence of the lead 22 used for conveying electronic current to the field winding l8.

The pole plates 5, It, are clamped by means of bolts 23, having threaded ends of reduced diameter, to which are threadedly secured nuts, as 24. When secured the closure ring 20, and the shell I9, which contains and supports the field winding 18, are firmly clamped between the pole plates 9, l0, and all the parts are properly spaced and positioned for operation of th motor.

The shell l9 tapers or narrows, to its inner diameter, the latter having about the same width as the rotor rim 4, so that the magnetic flux produced by the field winding 13 is concentrated on the rim. At the same time the inner diameter of the shell l9 fits snugly about the field fingers, and aligns these annularly. Each shading ring is made up of two annular shading plates, 15a, lib, generally similar, but with the inner one of the two, l5a, of reduced outer diameter, so that each shading ring i5, taken as a unit, tapers. The taper and spacing of the shading rings are such so that the shell i9 secures the inner shading plates, i511, firmly against th outer shading plates, wt, and hence against the respective pole plates 10 and II, and the inner shading plates llia in turn clamp the shell I9, thus forming an extremely rigid, yet simple, structure. By virtue of the tapered arrangement of the field shell is, and of the spacing and dimensioning of the shading rings l5, maximum utilization of space is accomplished, together with positive interlocking of parts, whereby the assembled rotor is rigid and compact, yet fabricated of a minimum number of simple parts susceptible of die pressing.

While we have described one specific embodi- 4 ment of our invention it will be clear that varie tions of construction may be resorted to without departing from the true scope of the claim as defined in the appended claim.

We claim:

In an electric motor or" the self-starting single phase hysteresis type, a pair of fiat disc shaped field plates, each of said plates having a plurality of pairs of integral projections bent in one direction at right angles to each of said plates, and at a fixed mean radius from the center of said plates, the projections of each of said plates all terminating in a common plan parallel with the plane of the field plates, a cylindrical rotor having a highly remanent rim, said rotor having a shaft coaxial therewith, bearings for said shaft fitted in central apertures of said field plates, a separate shading ring secured to each of said field plates and each force fitted over all the projections of its field plate, said shading rings having a greater outer radius and a smaller inner radius than the radius of said projections, a cylindrical field Winding coaxial with said field plates, and having a uniformly tapered cross section, a correspondingly tapered cylindrical plastic support for said field winding, said support having an inner diameter equal to the outer diameter of said projections and retaining said annular fingers in annular relation and a width at the inner diameter substantially equal to the width of said rim, said support having a width at its outer diameter equal to the desired spacing of said field plates in the assembled condition of said motor, an enclosing metal ring located between said field plates, and means for holding said field plates together in clamping relation to said metal ring, to said support in its outer diameter, and to said shading rings and said support taken at a point along its taper.

FRANCIS J. LANDGRAF. RICHARD P. LANDGRAF.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,959,391 Spencer May 22, 1934 2,237,960 Hansen et al Apr. 8, 1941 2,248,285 Reinhardt July 8, 1941 2,382,333 Poole Aug. 14, 1945 2,432,070 Sanborn Dec. 2, 19 7 2,437,201 Landgraf et a1 Mar. 2, 1948 is... eh, 

